"The British Army was sent to Northern Ireland in 1969 as a peacekeeping force between the Catholic and Protestant communities. Against a backdrop of sectarian violence, emerging paramilitary organizations began to contest British authority throughout the province. The British peace operations then evolved into counter-insurgency and counterterrorism operations. As the mission of the British Security Forces changed, the role of British intelligence became increasingly important. This thesis is a history of British intelligence operations against the Irish Republican Army (IRA) from 1969 to 1988. It critically examines the role of the British intelligence community in Northern Ireland and focuses on the major intelligence agencies that participated in the war against the IRA. The tradecraft of British intelligence is analyzed, particularly the use of informers as the primary vehicle of information about the IRA. Four representative operations conducted by British intelligence are presented as historical case studies and illustrate covert intelligence collection, propaganda operations, clandestine penetration, and the involvement of intelligence in so-called 'shoot-to-kill' incidents. The thesis concludes with an analysis of the uneasy relationship between Britain's aggressive intelligence community and the democracy that it serves."